In recent years, microchannel chips have been used to accurately and speedily analyze a trace substance such as protein and nucleic acid. Microchannel chips advantageously allow the amount of reagents or samples to be small, and are expected to be used for various uses such as laboratory tests, food tests, and environment tests.
It has been proposed to provide a micro valve in a microchannel chip to automate the process using microchannel chips (see, for example, PTL 1).
FIG. 1A and FIG. 1B illustrate a configuration of micro valve 10 disclosed in PTL 1. FIG. 1A is a plan view of micro valve 10 disclosed in PTL 1, and FIG. 1B is a sectional view taken along line a-a of FIG. 1A. As illustrated in FIG. 1A and FIG. 1B, PTL 1 discloses micro valve 10 including substrate 20 which is a flat plate, first layer 30 stacked on substrate 20, and second layer 40 stacked on first layer 30. First layer 30 includes first groove 31, first valve groove 32 communicated with first groove 31, second groove 33, second valve groove 34 communicated with second groove 33, and valve 35 disposed between first valve groove 32 and second valve groove 34. When first layer 30 is stacked on substrate 20, first groove 31, first valve groove 32, second valve groove 34 and second groove 33 respectively form first channel 36, first valve chamber 37, second valve chamber 38 and second channel 39. Second layer 40 includes, on a surface facing first layer 30, recess 41 whose shape in a plan view has a size greater than the size of the external shape of first valve chamber 37 and second valve chamber 38. When second layer 40 is stacked on first layer 30, recess 41 forms pressure chamber 42.
In micro valve 10 disclosed in PTL 1, when the pressure in pressure chamber 42 is increased, first layer 30 is pushed toward substrate 20, and valve 35 makes contact with substrate 20, thus stopping the fluid flow from first valve chamber 37 to second valve chamber 38. On the other hand, when the pressure in pressure chamber 42 is released, first layer 30 is sucked into recess 41, and first layer 30 bends toward recess 41. As a result, a gap is formed between substrate 20 and valve 35, and fluid flows from first valve chamber 37 toward second valve chamber 38.
When liquid is used as fluid which is supplied to the channel in disclosed in PTL 1, the liquid is sent from first channel 36 to the channel with valve 35 opened. By capillary action or external pressure, the liquid flows from first channel 36 to second channel 39 through a gap between valve 35 and substrate 20. Then, valve 35 is appropriately opened and closed as described above.